Cordless venetian blind



Dec. 11, 1945. H. J. COHN r 2,390,326

I CORDLESS VENETIAN BLIND Filed Dec. 16, 1943 2 Sheets-Sheet 1 IN VEN TOR. .5542040 U Coy/v,

BY v Z' WW'W A rroewsx H. J. COHN CORDLESS VENETIAN BLIND Dec. 11, 1945.

Filed Dec. 16, 1943 2 Sheets-Sheet 2 IN VEN TOR. 1742040 (I C OHM Patented Dec. 11, 1945 CORDLESS VENETIAN BLIND Harold J. Cohn, Los Angeles, Calif., assignor to Automatic Venetian Hardware Corporation, a corporation of California Continuation of application Serial No. 345,890,

July 17, 1940. This ap 1943, Serial No. 514,494

12 Claims. (Cl. 160-170) My invention relates generally to Venetian blinds, and more particularly to an improved type of Venetian blind hardware for use with conventional slats to form a blind which can be operated without the necessity of cords.

Heretofore, the Venetian blinds on the market have usually employed reduction gears, ratchets, or other rotative means operated by a cord for raising or lowering the blind. Likewise, it has been customary to employ a heavy tilting bar as the top slat of the blind, and to operate this tilting bar with a cord.

Obviously, the presence of cords dangling in front'of or along the side of a Venetian blind materially detracts from its appearance, and various expedients have been tried in an attempt to hide or eliminate these cords. However, so far as I am aware, no one as yet has ever offered to the market a truly cordless Venetian blind. This application is a continuation of my copending application, Serial No. 345,890, filed July 1'7,

One of the objects of this invention is to provide a novel Venetian blind structure which is raised by a spring motor adapted to have energy stored therein by the manual operation of lowering the blind.

Another object ofmy invention is to provide a Venetian blind of the character stated in which a plurality of spring motor elements cooperate to provide for increasing the amount of potential travel of the blind, with substantially no more force being necessary to lower a long blind than to lower a short one.

It is a further object of my invention to provide Venetian blind operating means which is universally adaptable to all sizes of blind, and which can be installed in windows of various widths by the simple expedient of varying the length of the drive shaft.

Another object of my invention is to provide ladder tape supporting means which permits the blind to be completely closed without substantial effort and without placing undue strain upon the respective parts.

A still further object of my invention is to provide a novel type of supporting tape, reeland guard, whereby it is made impossible for said tape to'come off of the reel even when the blind is raised too rapidly.

These and other objects of my invention will become apparent from the following description of a preferred form thereof, and by reference to the accompanying drawings, in which:

plicati'on December 16,

Fig. 1 'isa fragmentary front elevation of my improved blind installed in a window casing,

Fig. 2 is a vertical section taken at the line 2-2 in Fig. 1, showing the supporting and tilting mechanism in detail,

Fig. 3 is a front elevation, partially in section taken on line 3-3 of Fig. 2 of the parts shown in Fig. 2 with the ladder tapes removed.

Fig. 4 is a vertical section similar to Fig. 2 but taken at 4-4 in'Fig. 1, and showing .the tilting mechanism in one extreme position,

'Fig. 5 is an end elevational view partly cut away, taken at 5-5 in Fig. 1,

Fig. 6 is a front elevation, partly broken away, of a plural spring motor for use in my invention,

Fig. 7 is a vertical section of the bottom rail taken at "1-1 in Fig. 1 and illustrating how the lifting tape is-fastened to said base bar,

Fig. 8 is a perspective view of the lifting tape locking plate,

Fig. 9 is an exploded tab assembly,

Fig; 10 is a vertical section of the lifting tab taken along the line l0-l0 of Fig. 1, and

Fig. 11 is a sectional view of the inside of the pawl housing. i

Referring now to the drawings, and particularly to Fig, 1 thereof, it will be seen that the letter A generally designates a Venetian blind which is mounted in a window casing B. The blind A may be secured to the window casing by means of spaced mounting brackets 5, provided with bearings 6 therein. A horizontally-disposed perspective of the lifting shaft 1 is journaled in the bearings 6 with its ends projected through and beyond said bearings. Drums or reels 8 are adjustably secured to the shaft 1 as by set screws 9 and are disposed in spaced relatiomthe number of reels used depending upon the width of the blind. The drums 8 are provided with flexible metal lifting tapes l0 wound thereon, each'of said tapes being of a sufficient length to extend to the bottom of the blind when it is in its extended position.

The mounting brackets 5 are provided with downwardly and forwardly extending U-shaped hangers ll, each provided with a pair of spaced parallel arms- I 2-l2.' A generally rectangular or box-like tilting element or rocker I3 is pivotally mounted within each pair of arms |2i2 by means of trunnions l 5. I The slat structure of the blind may be constructed in conventional manner, and includes a plurality of slats I! and a bottom rail 18, supported in spaced relation by the usualladders which are preferably formed of fabric and comprise a forward ladder tape I9 struction will be described more in detail hereinafter.

Considering now the tilting mechanism in detail as best seen in Figs. 2, 3 and 4,itwill be noted that the forward wall of the right-hand rocker l3 extends above and is curved back rearwardly with respect to the main rocker frame, forming acurved lip 2|. The lower portion of the forward wall of the rocker is provided with a pair of apertures 22 and the forward ladder tape l9 passes up over the lip 2i and down across the rear thereof to be securely fastened :by clip means (not shown), cooperating with the apertures 22. By

thus extending the tape-bearing wall or lip 2| rearwardly and upwardly with respect to the pivot point, an increased range of effective rotation is given to the rocker l3, permitting the blind to be completely closed when the forward ladder tape is pulled down to its lowermost position, as shown in Fig. 4. It is thus seen that the effective lever arm is adequate to .easily rotate the blind, even when the rocker itself has been rotated to an angular position which causes the slats to approach their most nearly vertical position.

.As seen best in Fig. 3, side wall 23 of rocker I3extends above the lip 2|, and adjustably attached thereto as by screw 24 is an arcuate index plate 25 which is provided with a series of rectangularly-shaped apertures 26. A leaf spring 21 is rigidly fastened to the rear portion of hanger I I, and extends forwardly so that its upturned;

free end or lip 28 will resiliently engage the apertures 26. The tension in the spring 21 is adjusted' so that when the lip v28 engages an aperture 26, the rocker and consequently the blind is held in fixed position. However, a relatively,

small amount of force exerted on the ladder attached to the rocker bearing the index plate is sufiicient to disengage the spring lip 28 from the aperture 26 and permit the rotation of the rocker l3 on its trunnions 15. It will be apparent that the spring lip 26 will in turn engage consecutive apertures 26, and will hold the rocker in any one of several positions at varying angles of rotation as desired.

It will be apparent, of course, that all that is needed to rotate the rockers and slats forwardly (clockwise in Fig. 2) is a downward pull on the forward ladder tape [9. However, it is likewise apparent that an upward pull on the forward ladder tape l9 will not exert a direct force on the rocker sufficient to rotate it against the action of spring 21. This could, of course, be accomplished by a downward pull on the rear ladder tape [9a, but to get a satisfactory grasp on the rear tape would be very unhandy. To obviate this necessity and to make it possible to rotate the rocker both ways by merely exerting a pull on the tab 29, I provide a counter-balancing spring 30 fastened at its upper end to a portion of the bracket 5 and at its lower end to an arm 3| which may suitably be formed as an extension of one of the trunnions l5 of the rocker 13. This spring 30 is tensioned so that when an upward pull is exerted on the tab 29, thereby releasing some of the weight on the ladder tape l9, and consequently the rocker l3, the tension in the spring 30 will be sufficient to disengage the leaf spring lip 28, and cause the rocker l3 to rotate rearwardly (counter-clockwise in Fig. 2). Thus, it is seen that by the simple expedient of grasping the tab 29 and either raising it or lowering it, the blinds are tilted to any desired position. It will be noted that it is only necessary to have the index plate 25 and spring 21 on one of the rockers, since without a tilting bar the weight of the slats can be easily shifted and held in place as described. By thus leaving the other rocker free to rotate, less force is needed to tilt the blind.

' From an inspection of Figs. 9 and 10, it will be seen that I have provided a novel tab which is particularly adapted to provide the right type of pulling movement for the most efficient operation of my blind. A front plate 32 is formed with a centrally-disposed aperture and a depending arcuate finger 33, centrally disposed therein. A tab key 34 is provided with a bifurcated end, the tines 35 of which are bent at right angles adjacent their outer ends and are connected by .a cross-piece 36. As'will be seen, the finger 33 is adapted to be inserted in the space defined by the tines 35 and the cross-bar 36, the crossbar 36 finding an axial seat in the recessed portion of the finger 33, and the bent ends of the tines being accommodated by the portions of the aperture on either side of the finger 33. In assembling the tab mechanism, the plate 32 with its associated tab key 34 is held against the front of the forward ladder tape 19 and a complemenfront plate 32, thereby securely clamping the two plates with the ladder tape 19 between them and holding the tab key 34 in place, but allowing it to be rotated upwardly to a horizontalposition, at which point the bentends of the tines 35 engage the tape, which is backed up by the rear tab plate 38, thus preventing the tab key from rotating further.

As previously mentioned,-the lift tapes ID are wound on drums 8, and it will be apparent that if the blinds are raised'more rapidly than the natural speed of the drums, the tape will tend to climb off the drums and not be wound securely thereon, thus putting the blind mechanism out of commission for the time being. To eliminate this possibility, I provide a, guard 40 formed as the major arc of a circle and provided with fingers 4l adapted to loosely fit in andbe retained by slots 42 in the bracket 5. In cross-section, the guard 40 is U-shaped, with the base of the U fitting in to the groove provided by the circular side faces of the drum.

As will be seen from an inspection of Fig. 3., the width of the base of the U-shaped guard 49 is slightly smaller than the width of the groove in drum 8, and while permitting free movement of the drum, the guard effectively prevents the tape H] from rising off of the drum. Inasmuch as the reels are adjustably mounted on the shaft 1, their spacing depending upon the width of the blind being installed, it is essential that the guard 40 have a certain amount of play with respect to the drum, 1. e. that it in effect floats on the drum so as to be sure and not bind the same. Consequently, as mentioned, the fingers 4| fit loosely in the slots 42 so that the guard is permitted a cerof the front tab platen tain amount of rotational play with respect to the drum 8. It will also be noted that the outside diameter of the guard is but slightly greater than the outside diameter of the drum side faces, so that the base or bottom of the U rides well within the groove formed by said faces. I prefer to form the guard of resilient material so that it can be sprung'into position and need not be tightly held to maintain its relationship with respect to said reels. The loose fit of the bracket fingers 4| permits the guard to rotate or to adjust itself both rotationally and laterally with respect to the reels. I find this construction and assembly particularly valuable in that it greatly simplifies construction and provides the most efficient operation.

As previously mentioned, a spring motor 29 is provided for raising the blind and is disposed in operative relation with shaft 1 adjacent the right end thereof in Fig. 1. The spring motor unit includes a casing 49 secured to a mounting bracket 50 which is adapted to be fastened to the window casing B. A cup-shaped spring housing 5| is disposed within the casing 49 near the left end thereof, and is provided with a hub 52 extending through and journaled in the end walls of the casing. The hub 52 is secured to the main shaft 1 by pins 48 and 53. A flat coil spring 54 is disposed spirally within'the housing 5|, and has its outer end secured thereto and its inner end secured to a short hub 55 journaled in the easmg.

A second cup-shaped spring housing 56 is located within the casing 49 adjacent the housing 5|, and is rigidly attached to the hub 55. A fiat coil spring 59 is disposed spirally within the housing 56 and has its outer end secured thereto, and its inner end secured to a hub 60 which is in turn fixed to the right-hand side of the casing 49. Both the springs are wound in the same direction, so that only the outer coils thereof will first come in to play. In raising and lowering the blind, the above mechanism functions as follows.

In order to lower the blind, a person merely grasps the bottom rail I8 and pulls it downwardly. This downward movement of the bottom rail will effect an unreeling of the lift tapes H) from the drums 8 and cause rotation of said drums and the shaft 1, upon which they are mounted. The retation of the shaft 1 will also cause rotation of the spring housing 5| due to the pin connection therebetween. Continued rotation of the housing 5| will exert a, winding force on the outer coils of the spring 54 which will be transferred through the inner coils to the hub 55 and thence to the spring housing 56. As the tension in the spring 54 grows greater, the housing 56 will be caused to rotate, thereby winding spring 59 from the outside inwardly. Thus, it is seen that the force required to lower the blind a considerable distance is relatively small throughout the entire travel of the blind since, as is well known, the outer coils of a spiral spring are much looser Wound than the inner coils, and much less force is required to wind them up. This same condition is maintained when the spring 54 becomes sufficiently tightened to cause movement of the housing 56, since it isalso connected to the outer coils of its spring 59 so that continued downward motion of the blind and consequent rotation ofthe shaft 1 accomplishes a winding of both springs 54 and 59 from the outside with a minimum of efiort being expended. By properly proportioning the strengths and number of springs used, the pull can be kept substantially constant throughout the entire length-of travel.

' suitable means, such as screws 12.

The blind may be stopped and maintained at any desired height relative to the window casing by suitable means, such as centrifugal pawl stops similar to those used in ordinary window shades. These pawl stops are disposed at the left end of the motor casing 20, and are indicated generally by the numeral 43. The pawl stop mechanism ineludes an annular stop ring 44 surrounding the hub 52 and secured to the outer face of the casing 20. A cup-shaped housing 45 having a plurality of pawls or detents 46 pivotally mounted therein is disposed in cooperative relation with stop ring "4'4 and is secured to the hub 52, preferably by the pin 53. It will therefore be obvious that the ring 44 remains stationary and that the housing 45 will rotate relative thereto according to the rotation of the shaft 1 and the spring housing 5| functioning in the well-known manner to maintain the blind at any desired vertical adjustment.

In raising the blind from a lowered position, it is only necessary to free the pawls 46 by a quick downward pull and a sudden relaxing of the pull on the blind in the well known manner used in operating conventional window shades. As soon as the pawls are released, energy stored in the springs 54 and 59 causes rotation of the shaft 1 with the consequent raising of the blind by means of the lift tapes I. It will be apparent, of course, that in unwinding, the springs will function in the reverse order to that previously described in winding them up, and due to the fact that they are each wound from the outside in, so that only the loose outer coils of the springs are used, the flow of power will be even and uniform throughout the raising of the blind, so as to preclude any possibility of the blinds raising too fast.

It will be understood, of course; that in small installations where the blind is only a few feet long, that a one spring motor will be suflicient, i. e. the housing 56 and spring 59 may be dispensed with. However, I have found that in normalsized windows of six feet or more, it is highly advisable to provide a double spring motor as described, so that the amount of effort necessary to lower the blind to its lowermost position is kept at a minimum and is easily within the convenient range for the ordinary housewife. It will likewise be understood that if larger blinds are required, additional springs can be used in the motor attached in series in the manner heretofore described, so that the motor housing may contain two, three, four or any number of springs necessary to accomplish the easy and rapid raising of the blind. It will also be understood, of course, that if desired a plurality of separate motor units can be hooked up in series to accomplish the same result described.

Referring now to Fig. 7, wherein is illustrated my novel means for anchoring the lift tapes ID to the bottom rail l8, it will be seen that apertures are provided in the rail H3 in line with the lift tapes ID. A plate 10 provided with an upstruck curved lug H is fastened to the lower surface of the rail l8 across said aperture by any It will be noted that the plate 19 is provided with a pair of relatively small apertures 13 and 14 aligned with and to one side of the lug II. In fastening 'the supporting tape to the bottom rail, the end of the tape is led down across the lug 1| through the aperture 15 and then is threaded through the apertures 13 and 74, respectively. After the tape has been threaded through said apertures and crimped, the plate 10 is fastened in place on the lower side of the bottom rail, so that the tape is securely held, and will support the full weight of said rail and slats.

From the foregoing description of a preferred form of my invention, it will be seen that I have provided a truly cordless blind, wherein the blind raising and tilting mechanisms cooperate to produce a unitary result, to wit: a Venetian blind While the form of my invention illustrated and described herein is now deemed to be the pre ferred form thereof, I do notmean to limit myself to thatparticular form, but intend to include all equivalents thereof as defined by the appended claims.

I claim:

1. A cordless Venetian blind which includes: a plurality of horizontally-disposed slats supported by ladders; a pair of lift tapes adapted to raise said slats; a horizontal shaft mounted above said slats and provided with a pair of drums fixed thereon about which said lift tapes are wound; a spiral spring motor connected to said shaft and adapted to rotate the same and thereby lift said slats by the winding up of said lift tapes; and releasable means associated with said shaft adapted to lock said shaft against rotation.

2. A cordless Venetian blind which includes: a

plurality of horizontally-disposed slats supported by ladders; a pair of lift tapes adapted to raise said slats; a horizontal shaft of relatively small diameter journaled in brackets above said slats and provided with a pair of drums fixed thereon about which said lift tapes are wound; a spiral spring motor mounted at one end of said shaft and adapted to rotate the same and thereby lift said slats by the winding up of said lift tapes; and releasable means associated with said shaft to lock said shaft against rotation.

3. A cordless Venetian blind which includes: a plurality of horizontally-disposed slats supported by ladders separate pivotally mounted supporting members to'which the upper ends of said ladders are connected; releasable means for maintaining one of said members in a fixed position; a pair of lift tapes adapted to raise said slats; a horizontal shaft mounted above said slats and provided with a pair of drums fixed thereon about which said lift tapes are Wound; a spiral spring motor connected to said shaft and adapted to rotate the same and thereby lift said slats by the winding up of said lift tapes; and releasable means associated with said shaft adapted to lock said shaft against rotation.

4. A cordless Venetian blind which includes: a plurality of horizontally-disposed slats supported by ladders pivotally mounted supporting -members to which the upper ends of said ladders are connected; friction means associated with at least one of said supporting members adapted to maintain it in a fixed position; a pair of lift tapes adapted to raise said slats; a horizontal shaft mounted above said slats and provided with a pair of drums fixed thereon about which said lift tapes are wound; a spiral spring motor comprising a plurality of springs connected in series and to said shaft and adapted to rotate the same and thereby lift said slats by the winding up of said lift tapes; and releasable means associated with said shaft adapted to lock said shaft against rotation.

5; A cordless Venetian blind which includes: a plurality of horizontally-disposed slats supported by ladders, each of which is connected at'its upper end to a separate pivotally mounted supporting member; friction means associated with at least one of said ladder supporting members adapted to maintain it in a fixed position; a horizontal shaft mounted above said laddersupporting members and providedwith a pair of drums fixed thereon; a lift tape wound on each of said drums with its lower end connected to said slats and adapted to raise the same; a spiral spring motor connected to said shaft and adapted to rotate the same and thereby lift said'slats by the winding up of said lift tapes; and releasable means associated with said" shaft adapted to lock said shaft against rotation.

6. A cordless Venetian blind which includes: a plurality of horizontally-disposed slats supported by ladders; a pair of lift tapes adapted to raise said slats; a horizontalshaft mounted above said slats} and provided with a pair of drums fixed thereon about which said lift tapes are wound; a spiral spring motor comprising a housing connected to said shaft, a spiral spring within said housing with its outer end connected to said housing a second housing connected to the inner end of said first spring, and a spring in said second housing having its outer end connected thereto means holding the inner end of said second spring stationary, whereby the outer coils of said springs are stressed first in the normal operation of said blind; and releasable means associated with said shaft adapted to lock, said shaft against rotation.

'7. In a cordless Venetian'blind comprising a plurality of horizontally-disposed slats supported by ladders and adapted to be raised by a pair of lift tapes woundondrums mounted on a horizontal shaft above said slats, the combination with said shaft of a cylindrical housingco-axial and rotatable therewith, having a spiral spring therein which has its outer end connected to said housing a second housing connected to the inher end of said first spring rotatably'mounted in juxtaposition with said first housing, said second housing having a spiral spring therein with its outer end connected thereto means holding the inner end of said second spring stationary, whereby the lowering of said blind rotates said shaft and first housing to thereby stress said first spring and thereby rotate said second housing and stress said second spring, and releasable means for locking said shaft With said blind in lowered position whereby upon the release of said locking means the energy stored in said spiral springs will rotate said shaft in the opposite direction to wind up said tapes and raise said blind.

8. In a cordless Venetian blind comprising a plurality of horizontally-disposed slats supported by ladders and, adapted to be raised by a'pair of lift tapes wound on drums mounted on a horizontal shaft above said slats, the combination with said shaft of a cylindrical housing coaxial and rotatable therewith, having aspiral spring therein which has its outer end connected to said housing and its inner end held stationary, whereby the lowering of said blind rotates said shaft and 'housing to thereby stress said spring,

v and releasable means for locking said shaft with said blind in lower position Whereby'upon the .release of said locking means the energy stored in said spiral spring will rotate said shaft in the opposite direction to wind up saidtapes and raise said blind.

9. A Venetian blind comprising 'a'pluralityof horizontally-disposed slats, a pair of ladders for supporting said slats, a pair of lift tapes for raising said slats, a pair of brackets for supporting the upper ends of the ladders, a horizontal shaft rotatably supported by said brackets, a pair of drums, each having a tape receiving groove in its periphery mounted on said shaft for rotation therewith, one of said drums, being mounted ad- J'acent each of said brackets, said lift tapes being secured in said tape receiving grooves of said drums and adapted to be Wound therein, a guard loosely secured to each of said brackets having a portion adapted to ride loosely in the tape receiving groove of the adjacent drum to guide said tapes onto said drums during raising of said blind, spring motor means for rotating said shaft for raising said blind, and means for releasably locking said shaft against rotation.

10. A Venetian blind comprising a plurality of horizontally-disposed slats, a pair of ladders for supporting said slats, a pair of lift tapes for raising said slats, a pair of brackets for supporting the upper ends of the ladders, a horizontal shaft rotatably supported by said brackets, a pair of drums each having a tape receiving groove in its periphery mounted on said shaft for rotation therewith, one of said drums being mounted adjacent each of said brackets, saidlift tapes being secured in said tape receiving grooves of said drums and adapted to be wound therein, guard means secured to each of said brackets having a portion adapted to guide said tapes onto said drums during raising of said blind, spring motor means for rotating said shaft for raising said blind, and means for releasably locking said shaft against rotation.

11. A Venetian blind comprising a plurality of horizontally-disposed slats, a pair of ladders for supporting said slats, a pair of lift tapes for raising said slats, means for supporting the upper ends of the ladders, a horizontal shaft rotatably supported above said slats, a pair of drums each having a tape receiving groove in its periphery mounted on said shaft for rotation therewith, said lift tapes being secured in said tape receiving grooves of said drums and adapted to be wound therein, a guard loosely secured to each of said brackets and having a portion adapted to ride loosely in the tape receiving groove of the adjacent drum to guide said tapes onto said drums during raising of said blind, spring motor means for rotating said shaft for raising said blind, and means for releasably locking said shaft against rotation.

12. A Venetian blind comprising a plurality of horizontally-disposed slats, a pair of ladders for supporting said slats, a pair of lift tapes for raising said slats, means for supporting the upper ends of the ladders, a horizontal shaft rotatably supported above said slats, a pair of drums each having a tape receiving groove in its periphery mounted on said shaft for rotation therewith, said lift tapes being secured in said tape receiving grooves of said drums and adapted to be wound therein, guard means secured to each of said brackets and having a portion adapted to guide said tapes onto said drums during raising of said blind and hold said tapes in said grooves, spring motor means for rotating said shaft for raising said blind, and means for releasably locking said shaft against rotation.

HAROLD J. COHN. 

